The present application relates to a color filter used in, for example, a self-luminous element such as an organic EL (Electroluminescence) element, a method of manufacturing the color filter, and a light-emitting device using the color filter.
A self-luminous element such as an organic EL element includes a first electrode, an organic layer including a light-emitting layer and a second electrode in order on a substrate, and when a DC voltage is applied between the first electrode and the second electrode, electron-hole recombination occurs in the light-emitting layer to emit light. The emitted light may be extracted from a side closer to the second electrode, that is, from a side opposite to a side where a circuit including a TFT (Thin Film Transistor) or wiring is arranged so as to increase an aperture ratio. In the case where light is extracted from the side closer to the second electrode, a high-reflective metal electrode is typically used as the first electrode.
In a light-emitting device in which a plurality of such organic EL elements are formed, a refractive index in the elements is high (for example, a refractive index of 1.5 or over), so total reflection of light easily occurs at an interface with an air layer (with a refractive index of 1.0). Therefore, it is difficult to sufficiently extract emitted light to outside. Therefore, a technique of arranging a reflection plate (a reflector) on an light extraction side of the organic EL element so as to correct the emission angle of emitted light, thereby resulting in an improvement in light extraction efficiency has been proposed as described in Japanese Patent No. 3573393 and Published Japanese Translation No. 2005-531102 of PCT international application. In such a reflector, a plurality of projections are formed on a glass substrate so as to correspond to organic EL elements arranged, and a side surface of each projection is covered with a reflecting mirror film.
On the other hand, even in the case where the above-described plurality of organic EL elements emit, for example, three primary colors, that is, red (R), green (G) and blue (B) of light, it is effective to arrange color filters for these colors for the organic EL elements, respectively, so as to improve color purity or light-field contrast. In this case, the color filters for these colors are formed on one surface of a sealing substrate for sealing the organic EL elements so as to correspond to the organic EL elements, respectively. Then, the above-described reflector is bonded to surfaces of the color filters with an adhesive layer in between. In such a configuration, the emission angles of colors of light emitted from the organic EL elements are corrected in the projections in the reflector, and then the colors of light pass through corresponding color filters, respectively, to be extracted as the three primary colors of light.
As described above, the adhesive layer or the glass substrate is included between the color filters and the projections in the reflector. The adhesive layer or the glass substrate has a thickness of 10 μm or over, so a part of light emitted from the light-emitting layer may pass through the projections, and then may enter into color filters not corresponding to the color of the light in the adhesive layer or the glass substrate with the above-described thickness. Thereby, cross-talk between colors occurs.